Tauopathies are characterised by the pathological accumulation of misfolded tau. The emerging view is that toxic tau species drive synaptic dysfunction and potentially tau propagation before measurable neurodegeneration is evident, but the underlying molecular events are not well defined. Human non-mutated 0N4R tau (tau^WT) and P301L mutant 0N4R tau (tau^P301L) were expressed in mouse primary cortical neurons using adeno-associated viruses to monitor early molecular changes and synaptic function before the onset of neuronal loss. In this model tau^P301L was differentially phosphorylated relative to tau^wt with a notable increase in phosphorylation at ser262. Affinity purification - mass spectrometry combined with tandem mass tagging was used to quantitatively compare the tau^WT and tau^P301L interactomes. This revealed an enrichment of tau^P301L with ribosomal proteins but a decreased interaction with the proteasome core complex and reduced tau^P301L degradation. Differences in the interaction of tau^P301L with members of a key synaptic calcium-calmodulin signalling pathway were also identified, most notably, increased association with CaMKII but reduced association with calcineurin and the candidate AD biomarker neurogranin. Decreased association of neurogranin to tau^P301L corresponded with the appearance of enhanced levels of extracellular neurogranin suggestive of potential release or leakage from synapses. Finally, analysis of neuronal network activity using micro-electrode arrays showed that overexpression of tau^P301L promoted basal hyperexcitability coincident with these changes in the tau interactome and implicating tau in specific early alterations in synaptic function.

tau蛋白病的特征是错误折叠的tau蛋白病理性积累。新出现的观点是，在可测量的神经变性明显之前，有毒的 tau 蛋白会导致突触功能障碍和潜在的 tau 蛋白传播，但潜在的分子事件尚未明确定义。使用腺相关病毒在小鼠原代皮质神经元中表达人类非突变 0N4R tau (tau ^WT ) 和 P301L 突变 0N4R tau (tau ^P301L )，以监测神经元损失发生前的早期分子变化和突触功能。在此模型中，tau ^P301L相对于 tau ^wt被差异磷酸化，其中 ser262 处的磷酸化显着增加。使用亲和纯化-质谱结合串联质量标记来定量比较 tau ^WT和 tau ^P301L相互作用组。这表明 tau ^P301L与核糖体蛋白富集，但与蛋白酶体核心复合物的相互作用减少，并且 tau ^P301L降解减少。还发现了 tau ^P301L与关键突触钙-钙调蛋白信号通路成员相互作用的差异，最显着的是，与 CaMKII 的关联增加，但与钙调神经磷酸酶和候选 AD 生物标志物神经粒蛋白的关联减少。神经颗粒蛋白与 tau ^P301L的关联性降低，与细胞外神经颗粒蛋白水平升高相对应，表明突触可能释放或渗漏。 最后，使用微电极阵列对神经元网络活动进行分析表明，tau ^P301L的过度表达促进了基础过度兴奋性，这与 tau 相互作用组的这些变化一致，并且暗示 tau 参与了突触功能的特定早期改变。